Floating Bridge Angle - Intonation with 11/49 string set

[PTChristopher]

Yeah well Patrick is a ca-ca head.

I just felt like saying that.

[vejesse]

Actually I would say the position of the fret crown tangent point is more important than the nut because it's much more difficult to fix the frets. Think about it, when you set up a guitar do you leave the nut high? Of course not, you set the nut slots as low as you can get away with. I guess we can talk about the position of the nut starting point i.e. Buzz Feiten system but that's irrelevant unless you play open strings. And strings will vary from string to string of course.

Guitars don't play in tune, it's not possible to get them "in tune" like you can do with a wind or string instrument. And you can't get the consistency of a piano. But I'm sold on a custom bridge. Believe me, if you're pulling your hair out trying find the perfect location for a wooden archtop bridge it could be the ticket.

[PTChristopher]

Hi Ve'J,

I appreciate your point of view. It is not consistent with my own experiences, so it is a particularly valuable alternative outlook.

[vejesse]

Alternative Outlook - Don't they make jeans?

[xuoham]

Personally i see nothing obsessive in wanting a good intonation.
I'm serious about my instrument because i spend several hours a day on it that's all
Lead playing might be OK with a relatively bad intonation but to a certain degree i really hate chords with one note too sharp, of course not a few cents but like an eighth of a tone, it really sounds BAD to me (Like i don't hear this on records, especially solo guitar, i'm sorry Patrick2, you meant "perfect" while i mean "acceptable" ), instant turn off.

But of course being serious also means knowing when too much is too much and i would not feel good if i were obsessed by a few cents off and that my playing time would suffer from this obsession.
In my case it was more matters of an eighth tone off

The thing is, it's so wonderful to doubt about one thing and almost immediately get some nice people helping you out !
Why refrain ?

Jabberwocky, i hope not, LOL, this damn piece of felt, the tech guy is open minded (not really a "redneck", i'm in Japan) and i'm sure he won't see any problem there.

Anyway, problem solved to a great extent, so no more "obsession", just pure happiness, groove, chord melodies, and a big smile.

[Patrick2]

Yeah well Patrick is a ca-ca head.

I just felt like saying that.

I too feel better knowing you've gotten that off your chest. Now, please get back to being informative. The forum members rely upon you for things that they are currently unaware of. Do you really think there is anyone in this forum unaware that I am a "ca-ca head"??

[PTChristopher]

>>> Alternative Outlook - Don't they make jeans?

Well yes, now that they have "lost their edge" from their original soup-can underwear innovation.

(And no "Cream of Mushroom" jokes please. Oooops.)

Chris

[PTChristopher]

>>> Do you really think there is anyone in this forum unaware that I am a "ca-ca head"??

Unaware? Certainly not. I see it more as an opportunity to celebrate ca-ca-osity in the head department as a concept.

Interestingly, my spell checker does not like the "-osity" part, but is just fine with the "ca-ca" part.

[Patrick2]

>>> Do you really think there is anyone in this forum unaware that I am a "ca-ca head"??

Unaware? Certainly not. I see it more as an opportunity to celebrate ca-ca-osity in the head department as a concept.

Interestingly, my spell checker does not like the "-osity" part, but is just fine with the "ca-ca" part.

Yeah . . . well, you must be from the "nice" part of town. I still prefer to go with the time proven.. . . "shit head" . . . as opposed to ca-ca head. Kinda like . . . . Richard head. It just doesn't work! If someone is a dick head . . . then why mince words?? They're a dick head!

I learned a long time ago to be very wary of anyone who could accurately explain . . . . "inharmonicity".

[PTChristopher]

Just for fun,...

>>> I guess we can talk about the position of the nut starting point i.e. Buzz Feiten system but that's irrelevant unless you play open strings.

In my view moving the nut affects everything except open strings.

No, really.

Let's take a guitar and move (through the magic of television) the nut on the B string forward 1 mm.

Now the B string is slightly sharp. But of course we tune the instrument to the open strings, so we re-tune the string to B.

All the other notes will be flat since the frets are no longer the "correct" distance from the start of the scale at the original nut position.

AND, nearly-interesting is that the low fret positions will be flat by more than the upper fret positions.

So the C at the first fret will be flat by quite a bit, but the C at the 20th fret will be almost imperceptibly affected by our nut move.

Sooooo,

Bridge compensation affects only fretted notes (since we re-tune the string after moving the bridge) and it affects the notes proportionally based on their distance from the bridge. Bridge compensation has a stronger affect the farther up the FB you play.

Nut compensation, while considered exotic to some, affects only fretted notes (since we re-tune the string after moving the nut) and it affects the notes proportionally based on their distance from the nut. Nut compensation has a stronger affect the lower down the FB you play.

All in my view - with a little support from the actual way the strings go "twang".

Chris

[vejesse]

If you changed the take off point of the nut and then re tuned to that open string that would change things all up and down. But what if you tuned to all fretted notes? Wouldn't the nut still have no effect? Jazz players tend to play mostly all fretted notes, right? I do anyway, not that I'm a "real" jazz player.

I was under the impression that changing the nut T.O.P was a form of "nut compensation" to make the open strings more in tune with the fretted strings when both were played. PtChristopher are you familiar with the Buzz Feiten system? I've never set up a guitar with one of their "shelf nuts" and tuning offsets but I did measure one of those plastic nuts one time to see what the take off point variance was. I remember it being somewhere between .005" and .015" on some strings, while other were not compensated. Seems a bit gimmicky to me with all their seminars and training sessions. I do know guitar builders were experimenting with the nut T.O.P long before that.

[PTChristopher]

Hi Veej,

Yes, familiar with the Feiten and Earvana products.

My opinion is a long answer since you sort of have to cover everything for it to all make sense. I'll sit down tomorrow and respond.

Chris

[vejesse]

Maybe this belongs as it's own thread but after reviewing things here's my understanding.

If you play within the first three frets the notes appear to sound more sharp then they do farther up the neck. This is due to increased tension because of proximity to the height of the nut. Wound strings seem to be worse, especially in conjunction with fretted notes. By moving the nut closer to the bridge you counter act the tensioning effect by lowering the pitch.

With Buzz Feiten you use their special saddle offsets, with Earvana you leave the saddle conventionally compensated.

ok, I can see it, especially if you spend most of time playing cowboy chords. But why change the compensation at the bridge if you play mostly up the neck? The Earvana setup looks better, it's adjustable. You set the intonation normally, then move the nut back and forth until it works the best. You could even file off some of the shelf if you can't get it to come out perfect. Or, make your own shelf nut.

Sound about right? Is it worth the trouble?

[Patrick2]

[quote=xuoham;270665]

Personally i see nothing obsessive in wanting a good intonation.
I'm serious about my instrument because i spend several hours a day on it that's all

I think you might misunderstand me a bit when I use the term obsessing. We all seek good intonation. We also should all reject the concept of accepting poor intonation. However, there needs to be a point where we realize that the guitar is not an instrument where we will ever achieve absolutely perfect intonation on every one of the 120 possible fretting positions . . also to include the 6 possible open string notes. A good set up by a competent tech will . . or should get you as close to perfect as possible. As PTChris pointed out several times . . if your guitar is set up properly and you are able to hear intonation discrepencies when blowing . . . or even when chording . . then, you just might have issues somewhere other than the nut or the floating bridge.

Lead playing might be OK with a relatively bad intonation but to a certain degree i really hate chords with one note too sharp, of course not a few cents but like an eighth of a tone, it really sounds BAD to me (Like i don't hear this on records, especially solo guitar, i'm sorry Patrick2, you meant "perfect" while i mean "acceptable" ), instant turn off.

If you don't have the CD "Kenny Burrell & John Coltrane" . . (then you need to get it . . it's really great!!) . . do a google search and pull up the tune on that CD . . "Why Was I Born". It's a tune that features only those two guys. Listen to the part where 'Trane lays out and Kenny does a short chord solo. A good ear will immediately spot the intonation issues (or an out of tune guitar). But really . . . who cares??? Listen to what Kenny's playing man!

But of course being serious also means knowing when too much is too much and i would not feel good if i were obsessed by a few cents off and that my playing time would suffer from this obsession.
In my case it was more matters of an eighth tone off.

How the hell did you ever assess it to be an eighth tone off?? Did you actually strobe check it??

The thing is, it's so wonderful to doubt about one thing and almost immediately get some nice people helping you out !
Why refrain ?

Couldn't agree with you more on this. There's a wealth of knowledgeable cats on this forum. Priceless free consultation from true experts. We've all learned much from them. But, what I'm saying is that chasing perfection from an imperfect instrument is really an exercize in futility and frustration.

Anyway, problem solved to a great extent, so no more "obsession", just pure happiness, groove, chord melodies, and a big smile.

And that's the good news!

[Jabberwocky]

Man, calling someone Kaka (not the Brazilian footballer) in some countries can really lead to serious blows and fisticuffs. I think it is the equivalent of calling someone a C*NT.

I'm the redneck, xuoham, although it would be more appropriately called Orange or Persimmon Neck.

[xuoham]

Patrick,

"If you don't have the CD "Kenny Burrell & John Coltrane" . . (then you need to get it . . it's really great!!)"

Thanks a lot, i will check "Kenny Burrell & John Coltrane", i didn't know they made something together. I'm sure it's awesome, and you're right, who really cares if already hit by beauty in a musical moment.
Kenny Burrell impressed me big time with his rendition of Stolen Moments on his album called Moon and Sand or something like this. Oh, those voicings, they really shocked me when i was starting getting a bit of interest in "jazz" guitar, a long time ago.

"How the hell did you ever assess it to be an eighth tone off?? Did you actually strobe check it??"

Well, i know it's an eight of a tone simply because it's displayed on my clip-on tuner.
Maybe it sounds pedantic while i just meant ... erm, a little more than slightly off

Anyway i enjoy this thread ! You and Chris are so witty and knowledgeable, like old experienced cats ... i feel so "1st degree"

[PTChristopher]

Gents,

Today is absurdly busy, so I'll respond this evening (US EST).

I suggest a quick walk through bridge compensation so we are all on the same page, then nut compensation in its various forms.

Heckling is definitely allowed as far as I am concerned. Also, this is Paul's (xuoham) thread, so if Vejesse and I skip something that we both expect each other to know very well - don't let it pass without clarification.

Back later. Should be a fun continuation of the thread.

Chris

[MaxT]

Xuoham,
If you don't mind my going off at a tangent.....About that felt, was it successful in taming the harshness, from the transducers?
As you may recall, I have an Ibanez 105 f floating pickup, transducers at the bridge.
By the way, mine has the TOM metal saddle. The foot of the bridge is straight across.

[PTChristopher]

OK, so first bridge compensation:

When you tune up a string it follows a mostly straight path from the nut to the bridge. Yes there is a slight sag due to gravity in playing position, and a slight upward bow at the bridge and nut, particularly on new strings. There are also some very minor magnetic effects. But for all practical purposes the string is straight.

To play a note we need to press the string down to a fret. This means that the string is no longer on its straight path. So we have lengthened the path of the string and thus pulled the string to a higher tension, resulting in a sharp note. This is a problem.

Now when playing at the first fret we only press the string a short distance, but farther up the FB this distance, and resulting sharpness, increases.

We deal with this by moving the bridge saddle back.

To see what this does,...

If for example, we move the high E saddle back 1,5 mm (1/16"), this means that we have lengthened a 25" scale guitar's string length by 1/400th (0.25%). No big deal and we re-tune slightly back to E.

Now if we play at the first fret. Our absolute 1,5 mm (1/16") extension of the string is now a larger % of the total vibrating length. It is now (roughly) 1/376.5 (0.265%). So this compensation would make the string flat compared to the open string EXCEPT that we are stretching the string slightly to play the F.

Now lets play the 12th fret E. The 1,5 mm (1/16") extension is now 1/200 (0.5%) of the vibrating length of the string, so will make the note flatter still, but the distance we stretch the string to play the 12th fret E has also grown.

Now, the proportion of increased stretch as we play up the FB does not exactly match the increase % of the absolute 1,5 mm (1/16") compensation. But in most cases it is close enough. Life goes on; music is played.

BUT,...

In fact a string, when played, is stretched in up to four (arguably more than four) different ways, with some significant potential non-linearity to all four types of stretches.

The stretch to get a string to a fret is, however, the big one. And bridge compensation is in most cases good enough.

There are exceptions, and it may be interesting to see how those exceptions happen and what is done about it. We can also see how there are some attempts to commercialize the solutions - while blowing some smoke both to motivate sales and to escape the need for the rather tough walk through how it all works.

Anyway, there is absolutely no point in going further until we are clear on bridge compensation. It gets harder after this.

Let me know if this is "so-far, so-good" and we can move on to the other three ways the string stretches when played. (It's actually more than another three, but we'll skip what does not apply to compensation as a subject.)

Chris

[xuoham]

So, if i understand correctly, the lower the action, the smaller the compensation, right ?

or am i completely ... erm ... (cough)

[PTChristopher]

More on bridge compensation:

When you play, the string stretches. The core of a wound string stretches along its length - a very efficient way to increase tension.

The windings on a wound string are also stretched, but this stretch is in effect pulling the winding apart slightly. The effect of this on the tension of the string as a whole is so little that we can for all practical purposes ignore this winding stretch.

So, bridge compensation distance within a given strung set usually varies based more on the size of the string core, not as much on the overall gauge of the string.

The low E core is larger than the high E core (which is also the whole diameter of the high E string). And sure enough, we compensate the low E about 3X as much as the high E.

When using a t-o-m bridge, or carving a wooden bridge by hand, we can we also compensate a plain G far more than a wound G, which has a rather small core.

We can also compensate a B more than a wound G and less than a plain G. Ignore the string gauge, look at the core size and it all makes some sense.

In practice, with string gauges above .012 to .050 or so, and with a WOUND G - the variation from string to string is really not all that far from a linear increase as we go from high E to low E. So a simple angled (but otherwise straight) bridge is close enough for almost all players.

With lighter strings, a plain G, or for players who find that they experience the actual slight difference - it can be worthwhile to compensate each string individually.

But in such a case don't kid yourself:

- The difference is minor at best with heavier strings and a wound G. And this slight improvement is very often overwhelmed by other intonation artifacts that are not helped by bridge compensation.

- Making a bridge "perfect" for a given set of strings on a given day, WITH A GIVEN PLAYER'S GRIP is all well and good. But this moment of presumed perfection will not last as the strings age, and as new strings vary slightly in gauge and consistency of diameter and shape.

And so on.

But yeah, for very light strings and plain G, individual string bridge compensation is really a very good idea.

Chris

[PTChristopher]

>>> So, if i understand correctly, the lower the action, the smaller the compensation, right ?

Absolutely. Yes.

Chris

[PTChristopher]

OK, so various types of string stretch:

There have been a few attempts to name the types of string stretch, but unless I was writing a book on the subject I think I'll just number them.

Remember - strings follow a reasonably straight path from the nut to the bridge. If we alter this path, we lengthen it which increases string tension and raises the pitch of a note.

Stretch #1:

When we press a string down to make contact with a fret we stretch it. This raises the pitch. As we play farther up the FB we press the string farther to reach the fret. So the farther up the FB you play the sharper notes will get.

A given amount of bridge compensation becomes a larger % of the vibrating string length as you play farther up the FB. So the effect of bridge compensation increases as you play farther up the FB, which makes it quite effective in compensating for Stretch #1.

Stretch #1 is the most significant of the stretches. So only compensating for this is sufficient almost all of the time.


Stretch #2:

If #1 is the most important, then Stretch #2 is the stupidest and most unnecessary. It is unfortunately also VERY common. You should never have Stretch #2.

In principle, the nut should be at the same height as the frets. There are in fact some exceptions to this, but they are so small or obscure that for all practical purposes - THE NUT SHOULD BE AT THE SAME HEIGHT AS THE FRETS.

Sort of. But for now please accept this idea. We will get to the minor variations later.

In a typical factory, it is seemingly not practical to get the nut slots down at fret height. You do not know what strings the player will use, and it is time consuming to get a nut cut correctly.

So nuts are typically made too high for two likely reasons:

- It is easier to later lower them that to raise them.

- Too high does not make for a loud cowboy chord buzz that kills a sale at GC.

But if a nut is too high you get Stretch #2 ("The Devil's Stretch").

If the nut is the same height as the frets, then you have a simple linear change in distance from the straight string path to the fret as you play up the FB. (Ignore neck relief for now, we will get back to it much later.)

You have, in effect, zero stretch on an open string, the progressively increased stretch as you play higher frets.

BUT, if the nut is too high, you get a stretch not only down from the raised bridge to the fret crown, but also down from the raised nut. This may not sound all that bad as an idea, but here is the tricky and evil part:

The added stretch from a raised nut is GREATEST at the first fret, then becomes less of a factor as you play up the FB. It works exactly the opposite of Stretch #1 in terms of progressive increase. It is NOT able to be corrected by bridge compensation.

But wait a minute - doesn't the inverse nature of Stretch #2 balance out Stretch #1?

Not really. Yes the progressions of the effect of the stretches are opposite, but both make the string play sharp. One stretch does not cancel out the other at all.

AND, a high nut makes low position playing quite difficult. It also makes the overall action higher while providing no added buzz-reducing fret clearance toward the bridge.

(Oldane, we will definitely get to your angle on low nuts and the effect of relief as well. But right now I hope to stick to getting us all on the same page with regard to the ways strings stretch.)

In my view, you should never have Stretch #2. In practice, it is really more accurate to recommend that you should never, ever have a degree of Stretch #2 that has any practical effect on intonation.

OK, that was quite a bit. Let's see how that digests, then go on to #3 and #4.

Time for a Mayflower Brewery Porter.

Chris

[xuoham]

Oh, this is so useful !

I would never imagine that only the core counts .... i thought that the whole string counts.
Well, maybe it's explained in a basic mechanical physics manual or something like that.

So i guess it explains why on flat top acoustics one can often see a B string compensated saddle : the B has a bigger core than a wound G ! Wow ...


Also, regarding nut height, i checked my AF105 with a ruler ... Yessss!
My nut is at the same height as my frets. Happpy ! That's why it's such a pleasure to play chords on this neck, none of the typical "Devil's Stretch" that will sharpen one note and make a beautiful chord sound like a bad joke.
I see! Héhéhé ...

Thank you for your time Chris, really appreciated !

[PTChristopher]

Stretch #3 is easy to describe (so a nice break).

Stretch #3 comes from lateral movement of the string along the fret. It is how we bend notes.

Unfortunately, we also get some lateral movement when we do not want it.

For rock/blues players with very light strings, you can sometimes help by adding a bit more bridge compensation than might seem ideal. The idea is that the compensation will help with stray sharp notes in chords, even though strings can get a little flat way up the FB.

However, for rock/blues style solos, it is pretty easy for most advanced players to "naturally" add little left-hand squeezes and bends in solos to hit the notes as they wish way up the FB.

It works better than it sounds in writing.

For jazz players, the answer is practice (nothing new there,...) to avoid accidental lateral movement, particularly in tricky chord shapes. Fortunately, relatively heavier strings help as well.

And so on to the interesting Stretch #4 and the world of nut compensation,...